Additive design and manufacturing of a quadruped robot actuated by electrothermal effect of shape memory polymer

Soft robots possessing many flexible properties of locomotion beyond conventional rigid-body mechanisms have been recently investigated for various applications such as quadruped walkers, biomimetic actuators, and planetary explorations. Major issues concerning the recent development of robots include their flexibility of shape and controllability of motion as actuated by various means for different applications. Remarkable progress in developing innovative materials and structures has resulted in more advanced properties for fabrication using different methods. This paper reports a 4D printing method that can be elaborated by additive design and manufacturing (ADM) through fused deposition modeling (FDM) of conductive and insulating polymers simultaneously. With the polymeric composites deposited on paper, the functionality of the printed structure featuring shape memory effect (SME) on motion was illustrated for motion by electrothermal actuation with an electrical power supply, in which a reversible shape change of the structure in bending curvature was manipulated via heating and cooling. It showed digital control over adaptive displacement and the multilegged robot's speed in motion and gait types. In the future, various innovative structures and multi-component materials based on 4D printing of the present ADM scheme could be further explored for versatile robots with multiple functions of actuation and sensing.